> ## Documentation Index
> Fetch the complete documentation index at: https://docs.superoffice.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Database Mirroring requirements

> Prerequisites for running the Database Mirroring client on a customer-managed host.

The Database Mirroring client runs on a customer-managed host and connects **outbound** to SuperOffice. There is no public endpoint to host, no IIS site, no SuperOffice-issued certificate to install, and no inbound firewall rule to maintain.

A SuperOffice Online subscription that includes the **Database Mirroring** add-on is required. Custom apps that incorporate Database Mirroring need the same subscription.

## Host

* Any Windows host that can run a .NET 8 application.
* **Local administrator rights** for the initial provisioning and Windows Service installation.

Sizing depends on the size of the source database and the throughput required:

| Resource                         | Minimum                                                                                   | Recommended  |
| -------------------------------- | ----------------------------------------------------------------------------------------- | ------------ |
| RAM                              | 4 GB                                                                                      | 8 GB or more |
| Disk space (replica DB excluded) | Modest - the client binary and logs only                                                  |              |
| Disk space for the replica DB    | Plan for it to grow to roughly the size of the source CRM data, plus headroom for indexes |              |

## Software

* **.NET 8 runtime**, or use the self-contained build that ships with its own runtime.
* **Microsoft SQL Server** for the replica database. An empty database is recommended for the initial setup. SQL Server Express Edition is sufficient for small tenants; use Standard Edition (or higher) when you need SQL Agent, larger databases, or higher throughput.
* The SQL login used by the client needs **`db_owner`** on the replica database, so it can create and alter tables and maintain the internal `_ReplicationState` table.

## Network

* **Outbound HTTPS (443)** from the host to the SuperOffice Replication Dispatcher and Service URLs.
* No inbound ports.
* No SuperOffice-issued TLS certificates.

If you operate behind a strict outbound proxy, allow-list the SuperOffice replication endpoints (the exact URLs are shown in the terminal output after `provision` and in the [setup guide][1]).

## Backup

The replica database does not normally need its own backup strategy. The data is a copy of the SuperOffice cloud master and can always be re-synced. The exceptions are any **local additions** you make on top of the replica:

* Custom indexes, views, synonyms, triggers
* Application-specific tables that share the database

Back those up using your normal SQL Server backup process.

## Related

* [Set up the Database Mirroring client][1]
* [Overview][2]
* [SQL Server schema][3]

[1]: ./setup-guide

[2]: ./overview

[3]: ./sql-server-schema


## Related topics

- [Database mirroring](/en/online/mirroring/overview.md)
- [Set up the Database Mirroring client](/en/online/mirroring/setup-guide.md)
- [Troubleshooting Database Mirroring](/en/online/mirroring/troubleshooting.md)
- [Order database mirroring](/en/online/mirroring/order-database-mirroring.md)
- [Database Mirroring scenarios](/en/online/mirroring/scenarios.md)
- [CRM Online Database Mirroring](/en/api/nuget/crm-online-mirroring.md)